The development of therapies activating the cellular immune system (immunotherapy) is one of the fastest growing areas of cancer treatment. A critical part of clinical trials testing new immunotherapies, such as vaccines against tumor antigens, is monitoring tumor-specific immune responses to validate whether we are actually targeting and activating specific leukocyte subsets as intended, and whether immune activation correlates with clinical outcome. In addition, proper interpretation of the results of these immune response assays is needed to find ways of optimizing immunotherapies for future clinical trials. UT MD Anderson Cancer Center has recently established an immune monitoring core laboratory (IMCL) at its South Campus as part of the expansion of its immunotherapy program in cancer. This core laboratory houses a number of key technologies and infrastructure needed to support both clinical and pre-clinical assessment of T-cell and ARC function in cancer patients, including blood and tumor processing and storage, cell culture tools for in vitro stimulation, flow cytometry, and measurement of antigen-specific T-cell function using cytokine and CTL assays. We are also developing new and more sensitive T-cell assay technologies and have recently launched a new highly-sensitive non-radioactive CTL assay. The aim of the IMCL will be to support both preclinical and clinical aspects of all projects in this PO1 grant. Throughout the PO1 grant period, the IMCL will work with all the PO1 Projects by assisting in blood and tissue processing and will help develop multicolor flow cytometry and cellular assays to characterize the effects of pDC on anti-tumor T cell phenotype and function. One of our main activities will be to perform the immune monitoring in the clinical trial of Project 4 that will test the effects of TLR7 and TLR8 agonists during gplOO and MAGE-3 peptide vaccination in melanoma patients. The IMCL will process all peripheral blood mononuclear cell samples and tumor biopsies from this trial, establish a specimen storage bank, and develop an electronic specimen database during the clinical trial (Month 6 to Year 4.5 -Mpt/mo). In Year 1 we will work with Project 4 in optimizing and validating T-cell phenotypic and functional assays that will be used in Year 5 of the grant period to monitor the antigenspecific T cell responses in patients enrolled on the clinical trial. All immune monitoring measurements will be analyzed in collaboration with the Biostatistics and Data Management Core (Core C).